Mapping table managing method and associated storage system

Abstract

A mapping table managing method, performed in a storage system, includes organizing mapping information about the storage system into a plurality of pieces of partial mapping table (PMT) information and distributing and storing the plurality of pieces of PMT information in storage devices (SDs). The method includes searching for a storage location in an SD on which an access operation is to be performed, by using the PMT information stored in each of the SDs, and performing the access operation on a found storage location in the SD.

What is claimed is: 
     
         1 . A mapping table managing method in a storage system, the method comprising:
 organizing mapping information about the storage system into a plurality of pieces of partial mapping table (PMT) information and distributing and storing the plurality of pieces of PMT information in storage devices (SDs);   searching for a storage location in an SD on which an access operation is to be performed, by using the PMT information stored in each of the SDs; and   performing the access operation on a found storage location in the SD.   
     
     
         2 . The mapping table managing method of  claim 1 , wherein the mapping information comprises virtual address mapping information in which volume identification information and a virtual address are mapped with stripe identification information and a physical address, and stripe mapping information in which stripe identification information is mapped with respective pieces of memory block identification information of the SDs. 
     
     
         3 . The mapping table managing method of  claim 1 , wherein the mapping information includes virtual address mapping information in which volume identification information and a virtual address are mapped with stripe identification information and a physical address, the virtual address mapping information is classified into a plurality of pieces of partial virtual address mapping table information based on a value obtained by hashing the volume identification information, and the plurality of pieces of partial virtual address mapping table information are distributed and stored in the SDs. 
     
     
         4 . The mapping table managing method of  claim 3 , wherein the virtual address mapping information are classified into the plurality of pieces of partial virtual address mapping table information, based on a remainder obtained by dividing the volume identification information by the number of SDs of the storage system, and the plurality of pieces of partial virtual address mapping table information are respectively stored in the SDs. 
     
     
         5 . The mapping table managing method of  claim 1 , wherein the mapping information includes virtual address mapping information in which volume identification information and a virtual address are mapped with stripe identification information and a physical address, the virtual address mapping information is classified into a plurality of pieces of partial virtual address mapping table information based on a value obtained by hashing the virtual address, and the plurality of pieces of partial virtual address mapping table information are distributed and stored in the SDs. 
     
     
         6 . The mapping table managing method of  claim 5 , wherein the virtual address mapping information are classified into the plurality of pieces of partial virtual address mapping table information, based on a remainder obtained by dividing the virtual address by the number of SDs of the storage system, and the plurality of pieces of partial virtual address mapping table information are respectively stored in the SDs. 
     
     
         7 . The mapping table managing method of  claim 1 , wherein the mapping information includes stripe mapping information in which stripe identification information is mapped with respective pieces of memory block identification information of the SDs, the stripe mapping information is classified into a plurality of pieces of partial stripe mapping table information in which memory block identification information corresponding to the stripe identification information is mapped with each SD, and the plurality of pieces of partial stripe mapping table information are distributed and stored in the SDs. 
     
     
         8 . The mapping table managing method of  claim 1 , wherein the access operation comprises a write operation or a read operation with respect to SDs of the storage system. 
     
     
         9 . A storage system comprising:
 a plurality of storage devices (SDs) each comprising a random access memory (RAM) region and a non-volatile memory region; and   a controller configured to selectively transmit read commands and write commands to the plurality of SDs based on a log-structured storage environment, the controller being configured to organize mapping information about the storage system into a plurality of pieces of partial mapping table (PMT) information which are distributed into and stored in respective RAM regions of the SDs;   wherein the read commands and write commands received from the controller are executed using the PMT information stored in each of the SDs.   
     
     
         10 . The storage system of  claim 9 , wherein the mapping information includes virtual address mapping information in which volume identification information and a virtual address are mapped with stripe identification information and a physical address, the virtual address mapping information is organized into a plurality of pieces of partial virtual address mapping table information based on a value obtained by hashing the volume identification information, and the plurality of pieces of partial virtual address mapping table information are distributed and stored in the respective RAM regions of the SDs. 
     
     
         11 . The storage system of  claim 9 , wherein the mapping information includes virtual address mapping information in which volume identification information and a virtual address are mapped with stripe identification information and a physical address, the virtual address mapping information is organized into a plurality of pieces of partial virtual address mapping table information based on a value obtained by hashing the virtual address, and the plurality of pieces of partial virtual address mapping table information are distributed and stored in the respective RAM regions of the SDs. 
     
     
         12 . The storage system of  claim 9 , wherein the write command includes volume identification information, a virtual address, stripe identification information, and a physical address. 
     
     
         13 . The storage system of  claim 12 , wherein an update operation with respect to PMT information stored in a RAM region of at least one SD from among the plurality of pieces of PMT information, and a data write operation, are performed based on the write command. 
     
     
         14 . The storage system of  claim 9 , wherein the controller is configured to transmit a first read command to a first target SD in which PMT information corresponding to volume identification information and a virtual address included in the first read command is stored, and, the first target SD is configured to search for stripe identification information and a physical address corresponding to the volume identification information and the virtual address included in the first read command by using the PMT information, and, when a found physical address exists in the first target SD, data is read from a storage location indicated by found stripe identification information and the found physical address and transmitted to the controller, and, when the found physical address does not exist in the first target SD, the found stripe identification information and the found physical address are transmitted to the controller. 
     
     
         15 . The storage system of  claim 14 , wherein, when the controller receives the stripe identification information and the physical address from the first target SD, the controller is configured to transmit a second read command including the received stripe identification information and the received physical address to a second target SD in which the received physical address exists. 
     
     
         16 . A storage system comprising:
 a plurality of storage devices (SDs); and   a controller configured to
 organize mapping information about the storage system into a plurality of pieces of partial mapping table (PMT) information and distribute and store the plurality of pieces of PMT information in the SDs, 
 search for a storage location in an SD on which an access operation is to be performed, by using the PMT information stored in each of the SDs, and 
 perform the access operation on a found storage location in the SD. 
   
     
     
         17 . The storage system of  claim 16 , wherein the mapping information includes virtual address mapping information in which volume identification information and a virtual address are mapped with stripe identification information and a physical address, the virtual address mapping information is organized into a plurality of pieces of partial virtual address mapping table information based on a value obtained by hashing the volume identification information, and the plurality of pieces of partial virtual address mapping table information are distributed and stored in respective SDs. 
     
     
         18 . The storage system of  claim 16 , wherein the mapping information includes virtual address mapping information in which volume identification information and a virtual address are mapped with stripe identification information and a physical address, the virtual address mapping information is organized into a plurality of pieces of partial virtual address mapping table information based on a value obtained by hashing the virtual address, and the plurality of pieces of partial virtual address mapping table information are distributed and stored in respective SDs. 
     
     
         19 . The storage system of  claim 16 , wherein the controller is configured to transmit a first read command to a first target SD in which PMT information corresponding to volume identification information and a virtual address included in the first read command is stored, and, the first target SD is configured to search for stripe identification information and a physical address corresponding to the volume identification information and the virtual address included in the first read command by using the PMT information, and, when a found physical address exists in the first target SD, data is read from a storage location indicated by found stripe identification information and the found physical address and transmitted to the controller, and, when the found physical address does not exist in the first target SD, the found stripe identification information and the found physical address are transmitted to the controller. 
     
     
         20 . The storage system of  claim 19 , wherein, when the controller receives the stripe identification information and the physical address from the first target SD, the controller is configured to transmit a second read command including the received stripe identification information and the received physical address to a second target SD in which the received physical address exists.